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Background: Previous studies have found a strong correlation between internet search and public health surveillance data. Less is known about how search data respond to public health interventions, such as vaccination, and the consistency of responses in different countries. In this study, we aimed to study the correlation between internet searches for "rotavirus" and rotavirus disease activity in the United States, United Kingdom, and Mexico before and after introduction of rotavirus vaccine., Methods: We compared time series of internet searches for "rotavirus" from Google Trends with rotavirus laboratory reports from the United States and United Kingdom and with hospitalizations for acute gastroenteritis in the United States and Mexico. Using time and location parameters, Google quantifies an internet query share (IQS) to measure the relative search volume for specific terms. We analyzed the correlation between IQS and laboratory and hospitalization data before and after national vaccine introductions., Results: There was a strong positive correlation between the rotavirus IQS and laboratory reports in the United States (R2 = 0.79) and United Kingdom (R2 = 0.60) and between the rotavirus IQS and acute gastroenteritis hospitalizations in the United States (R2 = 0.87) and Mexico (R2 = 0.69) (P < .0001 for all correlations). The correlations were stronger in the prevaccine period than in the postvaccine period. After vaccine introduction, the mean rotavirus IQS decreased by 40% (95% confidence interval [CI], 25%-55%) in the United States and by 70% (95% CI, 55%-86%) in Mexico. In the United Kingdom, there was a loss of seasonal variation after vaccine introduction., Conclusions: Rotavirus internet search data trends mirrored national rotavirus laboratory trends in the United States and United Kingdom and gastroenteritis-hospitalization data in the United States and Mexico; lower correlations were found after rotavirus vaccine introduction., (Published by Oxford University Press on behalf of The Journal of the Pediatric Infectious Diseases Society 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.)

We examined potential risk factors on vaccine virus shedding and antibody seroresponse to human rotavirus vaccine (Rotarix) in Mexican infants. Two doses of Rotarix were administered to infants during the first two visits for their routine childhood immunization (∼8 and 15weeks of age) in Mexico City. Infant's characteristics and socioeconomic indicators were obtained, including history of long-term feeding practices (exclusively/predominantly breastfed and exclusively/predominantly non-breastfed). Two serum specimens were collected, one during the second rotavirus vaccine visit and one 7weeks later. Stool specimens were collected between days 4-7 after each of the two rotavirus vaccine doses. Rotavirus IgA and IgG titers in serum were determined by enzyme immunoassays (EIA) and rotavirus shedding in stool was assessed by EIA and confirmed by RT-PCR. The overall rotavirus IgA geometric mean titers (GMT) increased significantly post dose 2 from post dose 1 [176 (95%CI: 113-273) to 335 (238-471); p=0.020). Infants who were exclusively/predominantly breastfed were less likely to shed vaccine virus in stool than those who were formula-fed (22% vs. 43%, p=0.016). Infants who were breastfed had lower rotavirus IgA titers than those who were formula-fed after dose 1 [GMT: 145 (84-250) vs. 267 (126-566) p=0.188] and dose 2 [236 (147-378) vs.578 (367-910), p=0.007]. Infants who shed vaccine virus post dose 1 had significantly higher serum IgA GMT than those who did not shed [425 (188-965) vs. 150 (84-266), p=0.038]. Breastfeeding was linked with the reduction of both stool vaccine shedding, and IgA seroresponse. The reduced rotavirus replication in the gut and shedding after dose 1 may explain in part the lower IgA response in serum., (Published by Elsevier Ltd.)

Background: Mexico implemented routine childhood vaccination against rotavirus in 2007. We describe trends in hospitalization and deaths from diarrhea among children aged <5 years in Mexico before and 7 years after implementation of rotavirus vaccination., Methods: We obtained data on deaths and hospitalizations from diarrhea, from January 2003 through December 2014, in Mexican children <5 years of age. We compared diarrhea-related mortality and hospitalizations in the postvaccine era with the prevaccine baseline from 2003 to 2006., Results: Compared with the prevaccine baseline, we observed a 53% reduction (95% confidence interval [CI], 47%-58%) in diarrhea-related mortality and a 47% reduction (95% CI, 45%-48%) in diarrhea-related hospitalizations in postvaccine years, translating to 959 deaths and 5831 hospitalizations averted every year in Mexican children aged <5 years. Prevaccine peaks in diarrhea-related mortality and hospitalizations during the rotavirus season months were considerably diminished in postvaccine years, with greater declines observed during the rotavirus season compared with non-rotavirus season months., Conclusions: We document a substantial and sustained decline in diarrhea-related hospitalizations and deaths in Mexican children associated with implementation of rotavirus vaccination. These results highlight the public health benefits that could result in countries that adopt rotavirus vaccination into their national immunization programs., (© The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

Objective: To assess, by socioeconomic setting, the effect of nationwide vaccination against species A rotavirus (RVA) on childhood diarrhoea-related hospitalizations in Mexico., Methods: Data on children younger than 5 years who were hospitalized for diarrhoea in health ministry hospitals between 1 January 2003 and 31 December 2011 were collected from monthly discharge reports. Human development indexes were used to categorize the states where hospitals were located as having generally high, intermediate or low socioeconomic status. Annual rates of hospitalization for diarrhoea--per 10,000 hospitalizations for any cause--were calculated. Administrative data were used to estimate vaccine coverage., Findings: In the states with high, intermediate and low socioeconomic status, coverage with a two-dose monovalent RVA vaccine--among children younger than 5 years--had reached 93%, 86% and 71%, respectively, by 2010. The corresponding median annual rates of hospitalization for diarrhoea--per 10,000 admissions--fell from 1001, 834 and 1033 in the "prevaccine" period of 2003-2006, to 597, 497 and 705 in the "postvaccine" period from 2008 to 2011, respectively. These decreases correspond to rate reductions of 40% (95% confidence interval, CI: 38-43), 41% (95% CI: 38-43) and 32% (95% CI: 29-34), respectively. Nationwide, RVA vaccination appeared to have averted approximately 16,500 hospitalizations for childhood diarrhoea in each year of the postvaccine period., Conclusion: Monovalent RVA vaccination has substantially reduced childhood diarrhoea-related hospitalizations for four continuous years in discretely different socioeconomic populations across Mexico.

Objective: In Mexico, declines in childhood diarrhea deaths have been documented during 2008-2010 after rotavirus vaccine introduction in 2007. Because of concerns about variation in rotavirus vaccine efficacy by socioeconomic status, we compared reductions in diarrhea mortality in the lesser developed southern region versus the more developed northern and central regions of Mexico., Methods: We obtained data from national vital statistics on diarrhea deaths among children aged <5 years from 2002 through 2011. We compared region-specific diarrhea mortality before (2003-2006) and after (2009-2011) vaccine introduction. Regional vaccine coverage was estimated from administrative data, and socioeconomic status was assessed by using the Human Development Index., Results: In northern, central, and southern Mexico, the 2007 Human Development Index was 0.84, 0.82, and 0.77, respectively, and by 2010 an estimated 99%, 84%, and 89% of children aged <12 months had completed rotavirus vaccination. Diarrhea mortality among children <5 years old declined from 8.3, 17.9, and 28.5 deaths per 100,000 children during 2003-2006 to 4.5, 8.1, and 16.2 in 2009-2011 in northern, central, and southern Mexico, respectively, corresponding to rate reductions of 45%, 55%, and 43%. No significant differences were observed in rate reductions between regions (P > .8)., Conclusions: After introduction of rotavirus vaccination, marked and sustained declines in diarrhea deaths were seen among children in all regions of Mexico, including in the least developed southern region with the highest baseline diarrhea mortality. This finding indicates equitable vaccine delivery to children with varying risk of mortality and reaffirms the beneficial effects of rotavirus vaccination against fatal diarrheal disease.

The recent introduction of a rotavirus vaccine program in Mexico to control rotavirus disease, a common killer of children worldwide, has dramatically reduced the number of Mexican children dying and being hospitalized because of diarrhea. The successful introduction of a rotavirus vaccine program was preceded by several decades of focused research efforts to document the burden of disease and to generate the knowledge base to develop and deploy a vaccine. The postlicensure experience from Mexico demonstrates that evaluating the impact and safety of the vaccination program is vitally necessary for sustaining it. All in all, the immensely successful Mexico experience with control of rotavirus disease, if copied, could yield tremendously favorable results for children and parents worldwide.

Background: Single-strain rotavirus vaccine was added to the national immunization program in Mexico in May 2007. We assessed the impact of vaccination on the number of diarrhea-related hospitalizations in Mexican children in 2008 and 2009., Methods: We obtained data on all-cause diarrhea-related hospitalizations from January 2003 to June 2009 in Mexican children <5 years of age. We compared diarrhea-related hospitalizations during the 2008 and 2009 rotavirus seasons with the median number of diarrhea-related hospitalizations at baseline (2003-2006), before rotavirus vaccine introduction, at 306 Ministry of Health hospitals. We estimated vaccine coverage using administrative data., Results: A median number of 10,993 diarrhea-related hospitalizations (range: 9877-11958) occurred each prevaccine rotavirus season from 2003 to 2006 among children < 5 years of age. Diarrhea-related hospitalizations decreased by 11% (N = 9836) in 2008 and by 40% (N = 6597) in 2009. The greatest declines occurred in infants < 12 months of age during 2008 (25%) and 2009 (52%), with 1-dose rotavirus vaccination coverage of 74% and 89% during these years, respectively. A 43% decline was also noted among children 12 to 23 months of age during the 2009 season. No declines were noted during either 2008 or 2009 among unvaccinated children >24 months of age during the study period., Conclusions: Marked declines in diarrhea-related hospitalizations among vaccine-eligible Mexican children < 24 months of age have occurred during the first 2 complete rotavirus seasons following rotavirus vaccination. Rotavirus-specific surveillance and epidemiologic studies are necessary for a better understanding of the changes in disease epidemiology and public health impact from rotavirus vaccination.

Background: A phased introduction of a monovalent rotavirus vaccine occurred in Mexico from February 2006 through May 2007. We assessed the effect of vaccination on deaths from diarrhea in Mexican children in 2008 and 2009., Methods: We obtained data on deaths from diarrhea, regardless of cause, from January 2003 through May 2009 in Mexican children under 5 years of age. We compared diarrhea-related mortality in 2008 and during the 2008 and 2009 rotavirus seasons with the mortality at baseline (2003-2006), before the introduction of the rotavirus vaccine. Vaccine coverage was estimated from administrative data., Results: By December 2007, an estimated 74% of children who were 11 months of age or younger had received one dose of rotavirus vaccine. In 2008, there were 1118 diarrhea-related deaths among children younger than 5 years of age, a reduction of 675 from the annual median of 1793 deaths during the 2003-2006 period. Diarrhea-related mortality fell from an annual median of 18.1 deaths per 100,000 children at baseline to 11.8 per 100,000 children in 2008 (rate reduction, 35%; 95% confidence interval [CI], 29 to 39; P<0.001). Among infants who were 11 months of age or younger, diarrhea-related mortality fell from 61.5 deaths per 100,000 children at baseline to 36.0 per 100,000 children in 2008 (rate reduction, 41%; 95% CI, 36 to 47; P<0.001). As compared with baseline, diarrhea-related mortality was 29% lower for children between the ages of 12 and 23 months, few of whom were age-eligible for vaccination. Mortality among unvaccinated children between the ages of 24 and 59 months was not significantly reduced. The reduction in the number of diarrhea-related deaths persisted through two full rotavirus seasons (2008 and 2009)., Conclusions: After the introduction of a rotavirus vaccine, a significant decline in diarrhea-related deaths among Mexican children was observed, suggesting a potential benefit from rotavirus vaccination., (2010 Massachusetts Medical Society)

Background: The safety and efficacy of an attenuated G1P[8] human rotavirus (HRV) vaccine were tested in a randomized, double-blind, phase 3 trial., Methods: We studied 63,225 healthy infants from 11 Latin American countries and Finland who received two oral doses of either the HRV vaccine (31,673 infants) or placebo (31,552 infants) at approximately two months and four months of age. Severe gastroenteritis episodes were identified by active surveillance. The severity of disease was graded with the use of the 20-point Vesikari scale. Vaccine efficacy was evaluated in a subgroup of 20,169 infants (10,159 vaccinees and 10,010 placebo recipients)., Results: The efficacy of the vaccine against severe rotavirus gastroenteritis and against rotavirus-associated hospitalization was 85 percent (P<0.001 for the comparison with placebo) and reached 100 percent against more severe rotavirus gastroenteritis. Hospitalization for diarrhea of any cause was reduced by 42 percent (95 percent confidence interval, 29 to 53 percent; P<0.001). During the 31-day window after each dose, six vaccine recipients and seven placebo recipients had definite intussusception (difference in risk, -0.32 per 10,000 infants; 95 percent confidence interval, -2.91 to 2.18; P=0.78)., Conclusions: Two oral doses of the live attenuated G1P[8] HRV vaccine were highly efficacious in protecting infants against severe rotavirus gastroenteritis, significantly reduced the rate of severe gastroenteritis from any cause, and were not associated with an increased risk of intussusception. (ClinicalTrials.gov numbers, NCT00139347 and NCT00263666.), (Copyright 2006 Massachusetts Medical Society.)